Optical reflector



Dec. 20, 1927.

- E. LYNDON OPTICAL REFLECTOR .Filed April 7. 1923 INVENTOR Edward I yzzddb ATTORNEY xM/Cm Patented Dec.. 20, *1927.7

l T E EDWARD LYNDON, F NEW YORK, N. Y.

` OPTICAL REFLECTOR.

Application led April 7,

My invention relates to optical reiiectors which comprise a shell lor support of reinforced glass having a reflecting surface, and, more particularly. to reflectors wherein the glass is reinforced by'wre mesh imbedded therein.

One object of my invention is to enable the reflector to retain its function when the glass cracks under the action of excessive heat, or from mechanical causes, such as concussion and other violent effects.

Another object is to preventshatteri'n of thel lass. should the reector be pierce by a. bullet or exposed to the effects of gunfire,

and to hold the fractured segments together in such an eveutuality, preserving their relative positions and original form.

A further object of 1ny` invention' is to minimize the chance of cracking of the glass 30 `from the effect of excessive heat,- by facilitating the distribution of heat throughout the shell, or support., through heat conductors; and bv reducing the temperature of the reflector thereb at any point of heat concentration; and y further reducing this temperature in rovidin'g readily radiatine` means for the eat thus conducted out of the shell or support. v

A still further object of my invention is to combine a form of strengthening of the glass shell itself with a form of reinforcing applied to the back of said shell, so that leach transversal section of the glass sliell is supported at two points,'instead of having a` Se single support on the back, as now practised. This greatly increases the etiieiency of the reinforcing means, my vmethod of reinforcin"` being. somewhat analogous to supporting a earn at two points in lieu of supporting to it at one end.

Other objects of my invention will ap ear from the detailed description thereof w ich follows.

Referring to the drawings, Figures l and M6 2 are a.l front and a top view, respectively, of the glass support and the mould before the glass is shaped into the required form; Fiffure 3 is a front View of the same mould and glass support after the glass is shaped 5o into the required form; Figure 4 is a front view of the glass support and the mould before shapinfr the glass, according to another method used in my invention; 4Figure 5 isa sectional View of the optical reector in orm of my reflector; Figure 7 is a detail was. serian ne. cause.

of the ring encircling 4one form of my reflector; Figures'S, 81, 82, 8n are fragmentary sectional views of several forms of reflectors. y

Referring more particularly to Figures 1, 2 and 3. 1 is a mould or dish made of suitable lmaterial having a top surface shaped to conform with the desired form of the glass shell p of the reiector; 2 is a glass support which,

1n Figure l, is a fiat plate, and, in Figure 3, curve to-the shape of the mould; 3 is a wire mesh imbedded in the glass.

In Figure 4, the elements 1, 2 and 3 are identical with the corresponding elements in Figure l, while 4l is a supplementary portion of the mould having a bottom surface shaped to conform with the external surfaceof the reflector, the top surface of the portion `1 being shaped to conform with the back of the glass shell of the reflector.

In Figure 5, 2 is the lass shell, andl 5 any form of backing provi ed for this shell; 3 is the wire mesh imbedded in the glass; 6 the lring encircling the shell; all 1n cross section. The reiector is in position before the source of light which is lschematically indicated b 7 7; 8 is the reoion of the reflector within which the liglitv from 7 does not penetrate.l A

In Figure 6, the backing of the glass shell, @5 5, is reinforced by a wire mesh 9, while the glass is reinforced with the wire mesh 3. Figure 7 is a fragmentary view of the ring 6 with its flanges 10 and screw 11 to hold the ring in position and make the necessary aci-19o jus'tments therefor.

Referring toFigures 8, 81, '8 and 8, 5 is the backing for the glass shell,- this backing being provlded with a. reinforcing wire netting 9 in the type 88; 2 is a section of the glass shell, which is reinforced with a wire mesh in the types 81, 83 and 8a.

In the practice of my invention, I lay a slab of wire glass on the dish or mold, as shown in Figure 1, after which the mould` with the slab of glass is placed in a heating oven, where the, glass is heated until it softens and sinks into the depressed to of the mould. Then the tclnperature of t e ovenis gradually decreased until it reaches the l normal room temperature. The g ass shell is then removed, ground and polished on both ot' its surfaces, and ground along its periphery, the latter process including the rinding ofthe strands of wire imbedded it@ 1n the glass. to form a smooth edge. The succeedingy steps in preparing the finished 1 lin the glass.

article do not differ from the well known practice and need not be mentioned, except to say that the glass, after being silvered on the convex surface, may be supplied with any of the known forms of backing, among such forms being the reinforced types, both with, andwithout, metal or similar-strengthening layers.

Another method which I may use in the practice of my invention involves the twoart muld shown in Figure 4.. In this case, th parts of the mould are heated before the glass is placed the mould, and the slab of wire glass is also heated prior to placing it, suiiiciently so to render it plastic. Then the two heated parts of the mould are brought together under pressure', forcing the glass to assume the desired shape, the two parts of the mould being kept at the requisite distance to insure the' proper thickness for the glass shell. This shell is then removed from the mould and placed in an annealing oven. The succeeding steps are the same as in the first described process.

In one form of my invention, I may add an encircling ring 6, to the finished reflector. This ring is made of metal, either split at one point, or made in .two halves, the split ends'in either case having) flanges,10, which may be brought together y means of screws 11, vso as to make aclose fit of the ring along the periphery of the reiiector and, at the same time, bring the ends of the wire strands along the edge of the glass shell intov con- .tact with the metal ring, for purposes explained 'further below.

The function of the wire mesh imbedded v `in the glass is twofold. First, it serves to prevent disintegration of thereiector in the event that the glass is shattered, either because of the effect of excessive heat emanating from the source of light, or. from concussion, vibration, and the like, or, during military operations, from a shot piercing the reiiector, the wire mesh holding the shattered segments together. Equally important is the second function of the wire mesh, namely, its action in conducting the heat from point to point, and,'particularly, from points of concentrated heat to other points not so much aifected by heat.. For instance, the region 8 `of Figure 5, within which the light of the ,source 7 does not penetrate directly, is also less affected by the heat emanating from this source of light, as compjared with the region outside the cone 8. his inequality of heat effects is so Well knownthat in some cases it is advisable to supply this region with a heating surfaceA to equalize the strains in the glass." The wire mesh conducts the heat from the overheated region outside of the cone 8 tothe region inside the cone, thus effecting a more even distribution of heat and, therefore, of strains The heat conducting function of the wirel mesh embedded in the glass is further enhanced in one form of mv invention, viz, the type of reflector comprising the encircling met-al ring. This ring, being in Contact with the wire mesh,` as explained above,

serves to conduct the heat out of thereflec# ofthe glass shell, such as, for instance, illus r trated in the four Figures 8, in its relation to theV adherent backing and to the reinforcing metal strands. Assuming that the backing is a tenacious, adhesive material, the elementary segment is held in place (with more or less effect according to the nature of the backing) at one end only, like a beam supported at one end. On the other' hand, in my invention, the elementary segment is held in place at, or near, its center, as illustrated in Figure 8. argument to see that the latter method iS by far more effective in holdin the segment in place. 'The two metho s may be combined, Aas is illustrated in Figures82, 83, in which case the segment is supjported at two points, corresponding to a ported at two points, against the end su ported beam of Figure 8, to apply. the si e further. Thus, the wire mesh embedded in the glass may act as an inde endent reinforcing means, or, when combined with a reinforced back, co-operate with-v the latter in a well known and understood mechanical way.

Having' describedy my invention, I claim:

1; In an optical reiiector, the combination with a transparent vitreous body having a reflecting surface, of reinforcing means Itl needs noy cam supembedded inl said body and adapted to conbacking.

4. In an optical reector, the combination with a transparent vitreous body having'a reflecting surface, of a reinfoncin back therefor, and reinforcing means em' edded in said body and connected withl said-back along the periphery of said reiector.

5. In an optical reflector, the combination y with a transparent vitreous shell having a iso reiecting surface, of heat conducting means embedded in said shell, and a heat radiating member inp'contact with said heat conducting means. .t

6. In an optical reector, the combination with a transparent vitreous body having a 'reflecting surface, of heat conducting means embedded in said body, and a heat radiating memberencircling said body and making contact with said heat conducting means. 7. An optical reflector comprising a transparent vitreous support having a reiiectingy surface, a wlre mesh embedded 1n said support, a. metal ring encircling said support and making contact with said wire mesh, and means for adjusting said ring o n said support.

8. An optical reflector, comprising a transparent vltreous body having a reecting surace, a

reinforcing back therefor, a member` encircling said body, and reinforcing means embedded -in said body and coo eratmg with said reinforcing back through tl; ary of said enclrcling ring.

9. An optical reiiector comprising a transparent vitreous shell having' a, reecting surface, a protective and reinforcing back therefor, a reinforcing ring along the periphery of said reflector, and va Wire mesh embedded in said shell and co-operating with said back through the'intermediary of said reinforcing ring. y

10. An optlcal reiiector comprisin a transparent vitreous body having a re ecting surface, a metallic reinforcing back e intermeditherefor, and a wiremesh embedded in said' l vitreous body in contact with' the metal of said back along the periphery of said reflector.

EDWARD LYNDON. 

